In a typical cellular radio system, wireless terminals (also referred to as wireless mobile terminals, user terminals and/or user equipment nodes or UEs, mobile stations, etc.) communicate via a wireless communications network (also referred to as a wireless network, a radio access network, and/or a RAN) with one or more core networks. The wireless network covers a geographical area which is divided into cell areas, with each cell area being served by a RAN node, e.g., a radio base station (BS), which in some networks is also called a “NodeB” or enhanced NodeB “eNodeB.” A cell area is a geographical area where radio coverage is provided by the base station equipment at a base station site. Each base station communicates over an air interface using radio communication channels with UEs within the coverage area of the base station. The type of radio communication channels utilized between a base station and a UE define the radio access technology (RAT). There are circuit-switched radio access technologies that support circuit-switched operations, for example CDMA (code division multiple access) or GSM (Global System for Mobile Communications), and there are packet-data radio access technologies that support packet-data operations, for example High Rate Packet Data (HRPD), Long Term Evolution (LTE), and/or Third Generation Partnership Project (3GPP/3GPP2). A Radio Access Network may provide voice and/or data communication for subscriber wireless terminals.
Base stations of a wireless network may be arranged to provide overlapping cell areas over a geographical area of coverage. Conventional outdoor base stations, however, may provide insufficient coverage indoors. Accordingly, customer premises base stations (also referred to as customer premises eNodeBs) may be used to boost coverage in indoor environments. A customer premises base station, for example, may be coupled to a wireless network, for example, through a broadband network to facilitate wireless communications and/or handoffs to/from conventional outdoor base stations.
For example, a customer may install a customer premises base station in a home using a residential internet connection through a broadband network to provide communications between the customer premises base station and the wireless network. While the customer premises base station has an unconventional coupling with the wireless network (as compared with conventional outdoor base stations operated directly by the wireless network), the customer premises base station may provide a wireless interface that is transparent with respect to the customer's wireless terminal or terminals (e.g., cellular radiotelephone(s), smartphone(s), tablet/netbook/laptop computer(s), etc.). Accordingly, the wireless network may maintain a communication with the customer's wireless terminal (e.g., a telephone conversation, internet browsing session, etc.) when the wireless terminal moves between indoor and outdoor environments by handing off service between the customer premises and conventional base stations.
More particularly, a customer premises router may provide a data communications path between the customer premises (e.g., the customer's home) and the broadband network (e.g., using a modem such as a Digital Subscriber Line or DSL modem, a cable modem, etc.) to provide broadband data access for multiple devices at the customer premises. In addition to the customer premises base station, the customer premises router may be coupled to additional other devices at the customer premises (e.g., computing devices, VoIP phones, gaming devices, etc.). Accordingly, public reachability addresses may be used by the broadband network to address data communications to devices at the customer premises, and the router may then use private addresses to address the communications to the different devices at the customer premises. More particularly, a public reachability address may include an Internet Protocol or IP address for the router (e.g., an IPv4 address) and a User Datagram Protocol (UDP) port number of the router associated with a device at the customer premises. Stated in other words, the router may act as a Network Address Translation (NAT) device, and the customer premises base station may thus be unaware of the public reachability address that is used by the broadband network to direct communications for the customer premises base station.
In such a situation, the customer premises base station nay act as a client/host behind the router which acts as a NAT device, and the customer premise base station may need to communicate its public reachability address (e.g., its NAT public IPv4 address and source UDP port number) to a node or nodes of the broadband and/or wireless network(s). For example, the customer premises base station may need to provide its public reachability address to a policy controller at the broadband and/or wireless network(s).
A customer premises base station operating through a customer premises router may thus need to be aware of its public reachability address. Moreover, a customer premises base station operating through a customer premises router may need to repeatedly send keep-alive messages at an interval that is less than a time-out interval of the customer premises router so that the same public reachability address of the customer premises base station may be maintained, and/or so that the customer premises base station is continuously available to accept wireless terminal communications, hand-offs, calls, etc. If a communication coupling between the customer premises base station and the wireless communication network is interrupted (e.g., due to inactivity), a new public reachability address for the customer premises base station may be assigned when communication for the customer premises base station is reestablished, and/or calls may be interrupted and/or missed.
A customer premises base station may thus be coupled to a wireless communication network (e.g., to a 3GPP Evolved Packet Core) through a customer premises router and through a broadband network, and the customer premises base station may thus need to communicate its public reachability address to a policy and charging rules function (PCRF) server of the wireless network. More particularly, the customer premises base station may be coupled to a Security Gateway of the wireless network using an IPsec tunnel through the broadband network. The PCRF server may in turns use the public reachability address to identify a fixed connection through the broadband network that is assigned to the customer premises base station for policy enforcement. Conventionally, there is no control interface between the Security Gateway and a Mobility Management Entity (MME) of the wireless network, and the customer premises base station may transmit its public reachability address to the MME via a control interface that is routed through the IPsec tunnel.
While the IETF STUN protocol may allow a host/client behind a NAT device to discover its NAT public IPv4 address and source UDP port that are being used for a host session (see, Rosenberg et al., Session Traversal Utilities for NAT (STUN), RFC 5389, October 2008), the IETF STUN and IKE protocols are separate, protocols. On the other hand, IETF RFC's 4306 and 5996 may allow an IKEv2 peer (e.g., customer premises base station and/or wireless network security gateway) to discover whether it is behind a NAT device using IKEv2 signaling. See, Kaufman, Internet. Key Exchange (IKEv2) Protocol, RFC 4306, Dec. 2005, and Kaufman, et al., Internet Key Exchange Protocol Version 2 (IKEv2), RFC 5996, Sept. 2010. IETF protocols, however, may fail to provide suitable capability for a host/client device such as a customer premises base station behind a NAT device to securely discover and/or communicate its IPv4 public reachability address and source UDP port that is assigned to its current, communication session.